Page 1 of 1

indexed zero page X

Posted: Sat Aug 02, 2008 1:47 pm
by bruce_lee
Hi there,
i have written a function to simulate zero page index addressing mode, the trouble is i am not sure if my function increments the program counter the correct amount - currently it increments by 2, but when i tested the function on michaels 6502 simulator it incremented by 3 - i am not sure which one is right, mine or his :?, if someone can shed some light into this i would really appreciate it

many thanks

Posted: Sat Aug 02, 2008 5:02 pm
by kc5tja

Code: Select all

LDA zp,X
LDA (zp,X)
Both of these are 2-byte opcodes.